Gauges enjoy wide use in a variety of industries and applications. A gauge can typically include a measurement section and a display section. A measurement section can measure some condition (e.g., pressure, temperature, rate, position, time, concentration, density, force, intensity, physical dimension, velocity, acceleration, or other quantities, to name but a few). A display section can display the measured value.
Many gauges, typically analog gauges, include a display intended for human eyes. As but a few examples, a gauge can represent a measurement value with a deflected needle (or arrow), a variable bar size, or other geometric shape that varies according to a measured value.
Modern monitor and control systems are typically designed with a centralized monitoring system. However, because some gauges are designed for visual examination, they typically do not output an electrical signal and thus cannot be easily integrated with a central control system.
A first conventional approach to integrating a gauge into a system can involve the entire replacement of a gauge with a transmitting unit. An example of such a device can be found on the Internet at http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?ItemID=1611625135.
A drawback to such an approach can be that replacement of an entire gauge can be invasive. In the event the gauge is utilized in active process, the process may have to be shut down entirely as the gauge is replaced with a transmitting unit. Further, once a transmitting unit is installed, such a unit may have to be leak tested and also tested to ensure it is transmitting a correct signal. In addition, a conventional transmitting unit like that noted above can require wiring from the transmitter to a central location. This can require additional labor, and assumes suitable wiring paths are available at the site.
Another conventional approach can be found on the Internet at http://www.eissq.com/DialADC.html#Matlabcode. This approach includes capturing a digital image from a dial indicator with a webcam, and applying an algorithm to the data image. Drawbacks to such an approach can be that it is dependent upon optimal light conditions and can require considerable processing power to execute the algorithm.